2015 OL106 - an old comet?

See Sam Deen's message thread in MPML about 2015 OL106  being an "imposter trojan". 

I performed a simulation with 100 clones trying to achieve the same nominal orbital parameters and uncertainty as below.

From Horizons web interface:

(2015 OL106) Classification: Jupiter Trojan          SPK-ID: 3928029 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB Reference: JPL 2 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .2863714556023872 9.3239e-06   a 5.270192122670955 0.0001095 au q 3.760959533197438 2.9098e-05 au i 21.4224769951995 5.1601e-05 deg node 359.8294629245777 4.4923e-05 deg peri 313.6982197132379 0.0021834 deg M 145.9574151264247 0.0056942 deg tp 2457208.814574639116 (2015-Jul-05.31457464) 0.014075 TDB period 4419.143436948574 12.10 0.13773 0.0003771 d yr n .0814637508685576 2.5389e-06 deg/d Q 6.779424712144472 0.00014086 au   Orbit Determination Parameters    # obs. used (total)      39      data-arc span      850 days (2.33 yr)      first obs. used      2015-07-26      last obs. used      2017-11-22      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      4      norm. resid. RMS      .68872      source      ORB      producer      Otto Matic      solution date      2020-Mar-16 17:29:21   Additional Information  Earth MOID = 2.79199 au   Jupiter MOID = .530935 au   T_jup = 2.783

PL Small-Body Database Browser

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	Clones			Target
	mean	sd		mean	sd
q	3.76096161305	2.919293e-05		3.7609595332	2.9098e-05
e	0.28637206423	9.3409e-06		0.2863714556	9.3239e-06
i	21.42247962456	5.175126e-05		21.4224769952	5.1601e-05
peri	313.69838452814	0.00218824566		313.69821971324	0.0021834
node	359.82946145114	4.488101e-05		359.82946292458	4.4923e-05
tp	2457208.81561007	0.01411030776		2457208.81457464	0.014075

Simulation done with Mercury6 software with these parameters:

)---------------------------------------------------------------------
) Important integration parameters:
)---------------------------------------------------------------------
 algorithm (MVS, BS, BS2, RADAU, HYBRID etc) = BS
 start time (days)= 2459167.50000
 stop time (days) = -1d8
 output interval (days) = 100
 timestep (days) = 0.05
 accuracy parameter=1.d-12
 ejection distance (AU)= 100

The simultion resuls are as follows:

78 clones arrived into the solar system from a distance greater than 100 AU

So it seems that this asteroid has the potential to be an old comet!

Cheers,

Alessandro Odasso

Asteroid 2005 QQ87

JPL/HORIZONS                     (2005 QQ87)               2014-Dec-03 15:43:43
Rec #:530344 (+COV)   Soln.date: 2014-Sep-12_12:17:06     # obs: 52 (2005-2014)
 
FK5/J2000.0 helio. ecliptic osc. elements (au, days, deg., period=Julian yrs): 
 
  EPOCH=  2454437.5 ! 2007-Dec-03.00 (CT)          Residual RMS= .27303        
   EC= .3031120594670821   QR= .6968320203827482   TP= 2454614.6607866557      
   OM= 155.0827683457962   W=  54.47813449079076   IN= 33.94229881367796       
   A= .9999197573283777    MA= 185.3679511050879   ADIST= 1.303007494274007    
   PER= .9999              N= .985726285           ANGMOM= .016392167          
   DAN= .77208             DDN= 1.10215            L= 204.3708543              
   B= 27.0291607           MOID= .0794868          TP= 2008-May-28.1607866557  
 
Asteroid physical parameters (km, seconds, rotational period in hours):        
   GM= n.a.                RAD= n.a.               ROTPER= n.a.                
   H= 22.7                 G= .150                 B-V= n.a.                   
                           ALBEDO= n.a.            STYP= n.a.                  
 
ASTEROID comments: 
1: soln ref.= JPL#11, OCC=1
2: source=ORB 

These are two graphs showing the movement of the asteroid in a frame of reference co-rotating

with earth

Sun is at (0,0) and Earth is at (1,0).

In this moment, the asteoroid seems a quasi-satellite of earth

 

However, the libration seems quite fast, so the "quasi-satellite" status is absolutely 

temporary:

Cheers,

Alessandro Odasso 

Potential Asteroid Pairs

This is a list of potential asteroid pairs (asteroid1 - asteroid2).

Asteroid1 and Asteroid2 have been very close in the past: whether this happened by chance or not needs to be confirmed. In fact, what you see here is just the result of a simulation made with Mercury software.

I am aware that any simulation result must be taken with caution. Besides any trivial error that I might have done, one must be aware that the simulation itself had these characteristics:

• no attempt to take into account Ceres, Pallas and Vesta
• no attempt to take into account non gravitational forces
• use of hybrid simplectic algorithm that is fast but maybe a little less precise than other algorithms

Once said this, if you look at the above list, you can get more details.
Open the embedded PDF in full screen mode, you will be able to click and follow the hyperlinks.

The hyperlink in column "Asteroid1_Asteroid2_Distance" will open a page  showing how the distance between the two asteroids varied in the past.

The hyperlink associated to the asteroid names will open a page of the AstDys system where you will find useful details that may help to put things in context.

For example, I already listed what I think is a useful information provided by AstDys , i.e.whether it is possible or not to identify a parent body for the family of the two asteroids of the pair and which are the nearest family members.

In some cases, the AstDys service is unable to identify a parent body for the asteroid pair:  it is not clear to me if this happens because the pair is really isolated or because it has not yet been associated to a family.
The fact that no parent body is identified does not  necessarily mean that the asteroid pair is not interesting and I guess that the opposite is also true: finding a parent body does not prove that the two asteroids are a divorced pair.

Let's look at the most important parent bodies listed above counting them.
This is the result :

Parent Body	Total
-	28
(158) Koronis	26
(135) Hertha	5
(4) Vesta	5
(1338) Duponta	3
(2076) Levin	2
(15) Eunomia	1
(1547) Nele	1
(16286) 4057P-L	1
(170) Maria	1
(20) Massalia	1
(606) Brangane	1
(668) Dora	1
(93) Minerva	1

In conclusion, about 1/3 of the cases belong to the (158) Koronis family, another 1/3 of the cases can not be related to known families, the last 1/3 is spread in other families.

Inside the Koronis family, the asteroid that more often appear to be related to the asteroid pairs are:

(11728) Einer

(2226) Cunitza (158) Koronis Kind Regards, Alessandro Odasso